Robert N. Jones

Correlates of survival in patients with postinfarction ventricular septal defect

Prognostic indicators of survival in 42 consecutive patients (21 men and 21 women) with postinfarction ventricular septal defect were reviewed. Infarct location was anterior in 57%, inferior in 33%, and combined in 10%. The hospital mortality among 9 patients not receiving surgical therapy was 100%. Of the 33 surgically treated patients, 19 (58%) survived. Time from diagnosis to operation, ventricular function, and presence or absence of shock were analyzed in a logistic regression model to determine which factors carried independent prognostic value. Shock was independently predictive of operative mortality ( p p = 0.059). Kaplan-Meier survival estimates revealed 1-year survival of 70%, 5-year survival of 55%, and 10-year survival of 20%. Seventy percent of survivors were in New York Heart Association class I or II. These data show that, irrespective of ventricular function or timing of operation, the development of shock is the most important predictor of survival in postinfarction ventricular septal defect. The higher mortality in patients with inferior infarction may be associated with a greater degree of right ventricular infarction and consequent dysfunction. Finally, long-term survival and excellent functional recovery can be achieved in patients undergoing operation.

Effect of hypothermia on changes in high-energy phosphate production and utilization in total ischemia

Abstract The effect of temperature on the rate of production, utilization and destruction of high-energy phosphate in total ischemia was investigated in the dog heart. These studies were performed utilizing a new model of ischemic injury which was designed to test the effect of interventions on the metabolism and structure of ischemic myocardium. In this model, the normal heart was isolated from the circulation in vivo and was arrested immediately with hyperkalemic, oxygenated, autogenous arterial blood prior to the induction of total ischemia. Left ventricular pressure changes in the isolated heart were used to time the onset of ATP depletion to the levels associated with the development of contracture-rigor. Decrements in temperature progressively slowed both ATP production from anaerobic glycolysis and ATP utilization and delayed but did not prevent ATP depletion and the onset of contracture-rigor. Reserve supplies of high-energy phosphates were utilized and much of the adenine nucleotide pool was destroyed at all temperatures studied. Anaerobic glycolysis provided more than 80% of the high-energy phosphates utilized by the ischemic cell at all temperatures but always ceased when ATP levels decreased to 1–2% of control. The results demonstrate that the protective effect of hypothermia in total ischemia is due to a proportional slowing in rates of energy production and utilization. Consequently, hypothermia only delays the depletion of the high-energy phosphate reserves of the myocyte and the destruction of the adenine nucleotide pool.

The coronary pressure-flow determinants left ventricular compliance in dogs.

Displacement of the left ventricular diastolic pressure-dimension relationship (change in compliance) has been observed with alterations in coronary perfusion pressure. The relative contribution of coronary (myocardial) blood flow, as compared with the perfusion pressure at which flow occurs, was studied in 10 dogs during diastolic relaxation by potassium arrest during cardiopulmonary bypass. The normalized left ventricular pressure-dimension relationships, obtained during passive, gradual filling of the left ventricle (0–20 mm Hg) were shifted progressively to the left as coronary perfusion pressure was Increased. Myocardial blood flow was 0.06 ml/mg per min ± 0.02 ml/mg per min (mean ± SEM) at a coronary perfusion pressure of 40 mm Hg and increased to 0.38 ml/mg per min ± 0.11 ml/mg per min as the coronary perfusion pressure was raised to 120 mm Hg. Addition of adenosine significantly Increased myocardial blood flow by 109% at a coronary perfusion pressure of 80 and by 147% at a coronary perfusion pressure of 120 mm Hg, but caused no additional significant shifts in the pressure-dimension relationships, compared to the same coronary perfusion pressures without adenosine. Coronary perfusion pressure, and not coronary blood flow, is a more direct determinant of cardiac diastolic properties.

Candida mediastinitis after a cardiac operation

Candida mediastinitis is a rare condition characterized by a high mortality and chronic morbidity, Including the present review, only 39 cases have been described, 67% occurring after a cardiac operation. Candida mediastinitis has a 55% mortality in the postoperative setting and a mortality of 92% among patients without a prior cardiac procedure. Although no patient survived Candida mediastinitis without surgical drainage of the mediastinum, survival was 85% among 13 patients who underwent operative mediastinal drainage. Chronic wound infection developed in 6 survivors of operative drainage without muscle flap closure, but in all patients closed with vascularized flaps, healing ultimately occurred. Aggressive surgical management with mediastinal drainage, sternal debridement, and early wound closure with vascularized flaps are essential to minimize the otherwise high morbidity and mortality of Candida mediastinitis.

High Energy Phosphates, Anaerobic Glycolysis and Irreversibility in Ischemia

The effects of severe regional myocardial ischemia in vivo and total ischemia in vitro on energy production by anaerobic glycolysis in dogs are described. The critical feature of ischemic injury in terms of the adenine nucleotide pool is the fact that the demand of severely or totally ischemic tissue for HEP exceeds the capacity of the damaged myocytes to produce it. The consequent depletion of ATP to very low levels and the destruction of the adenine nucleotide pool are associated with, or may be casually related to, the loss of cellular viability.

Transmural Gradient in High-Energy Phosphate Content in Patients with Coronary Artery Disease

In 16 patients undergoing elective coronary artery bypass, transmural biopsies were performed during bypass but before global ischemia. Subendocardial and subepicardial halves were separately assayed in each sampled tissue. Adenosine triphosphate (ATP) levels, total adenine nucleotide content (sigma Ad), and creatine phosphate (CP) content were significantly higher (p less than 0.005) in the subepicardium than the subendocardium in regions of the heart distal to major occlusions: 35.36 +/- 2.12 nmole/mg versus 28.7 +/- 1.7 (ATP), 42.24 +/- 2.04 versus 35.6 +/- 1.6 (sigma Ad), and 29.99 +/- 4.32 +/- versus 16.35 +/- 3.48 (CP). The opposite was true in two hearts with normal coronary arteries, in which high-energy phosphates tended to be higher in the subendocardium than the subepicardium. A transmural metabolic gradient therefore exists in regions of the myocardium distal to significant coronary occlusive disease. The subendocardiums relative depression in metabolic reserve cold determine its susceptibility to ischemic damage and influence techniques designed to preserve the heart during ischemia.